eprintid: 3862 rev_number: 6 eprint_status: archive userid: 69 dir: disk0/00/00/38/62 datestamp: 2018-01-16 10:10:51 lastmod: 2018-01-16 10:10:51 status_changed: 2018-01-16 10:10:51 type: article metadata_visibility: show creators_name: Lepidi, Marco creators_name: Bacigalupo, Andrea creators_id: creators_id: andrea.bacigalupo@imtlucca.it title: Multi-parametric sensitivity analysis of the band structure for tetrachiral acoustic metamaterials ispublished: inpress subjects: TA subjects: TH divisions: CSA full_text_status: none keywords: Periodic materials; Acoustic metamaterials; Wave propagation; Perturbation methods; Sensitivity analysis abstract: Tetrachiral materials are characterized by a cellular microstructure made by a periodic pattern of stiff rings and flexible ligaments. Their mechanical behaviour can be described by a planar lattice of rigid massive bodies and elastic massless beams. The periodic cell dynamics is governed by a monoatomic structural model, conveniently reduced to the only active degrees-of-freedom. The paper presents an explicit parametric description of the band structure governing the free propagation of elastic waves. By virtue of multiparametric perturbation techniques, sensitivity analyses are performed to achieve an analytical asymptotic approximation of the dispersion functions. The parametric conditions for the existence of full band gaps in the low-frequency range are established. Furthermore, the band gap amplitude is analytically assessed in the admissible parameter range. In tetrachiral acoustic metamaterials, stop bands can be opened by the introduction of intra-ring resonators. Perturbation methods can efficiently deal with the consequent enlargement of the mechanical parameter space. Indeed high-accuracy parametric approximations are achieved for the band structure, enriched by the new optical branches related to the resonator frequencies. In particular, target stop bands in the metamaterial spectrum are analytically designed through the asymptotic solution of inverse spectral problems. date: 2017 publication: International Journal of Solids and Structures publisher: Elsevier id_number: doi:10.1016/j.ijsolstr.2017.12.014 refereed: TRUE issn: 0020-7683 official_url: http://doi.org/10.1016/j.ijsolstr.2017.12.014 citation: Lepidi, Marco and Bacigalupo, Andrea Multi-parametric sensitivity analysis of the band structure for tetrachiral acoustic metamaterials. International Journal of Solids and Structures. ISSN 0020-7683 (In Press) (2017)